• UNO for Arduino---------------------- expansion board
  • 8 ------------------------ EN ( stepper motor driver enable , active low )
  • 7 ----------------------- Z.DIR (Z -axis direction control )
  • 6 ----------------------- Y.DIR (Y -axis direction control )
  • 5 ----------------------- X.DIR (X -axis direction control )
  • 4 ---------------------- Z.STEP (Z -axis stepper control )
  • 3 ---------------------- Y.STEP (Y -axis stepper control )
  • 2 ---------------------- X.STEP (X -axis stepper control )

Note: When inserting the A4988 module, must be careful not to insert opposite. Stepper motor wiring as follows:
2A, 2B is a group (red, green), 1A, 1B is a group (blue, yellow), if want to change direction, can be change the position of one group , for example 2A, 2B mutually exchanged.